issue: February 2006 APPLIANCE Magazine Engineering Design Recommendations for Electromagnetic Compatibility	Share  Printable format  Email this Article  Search
by Sankar Kumar Rajan and Vijay Chari, Satyam Computer Services, Ltd. The following addresses electromagnetic compatibility in consumer appliances, with a focus on the design of electronic control cards that need to meet governing standards.

Today, many appliance design issues are addressed through conventional design methods such as design for Six Sigma (DFSS) techniques, which enable the designer to predict problems in advance. However, meeting the various national and international electromagnetic interference/ electromagnetic compatibility (EMI/EMC) standards is still an area of concern, and a lot of work needs to be done. This is all the more valid in the present day with the introduction of more and more electronics and wireless gadgetry.

The majority of the appliances on the market have an electronic control card consisting of microcontroller (MCU)-based circuitry that takes care of the entire operation of the appliance. The level of complexity of design varies depending on the features, price point and the target market. About 80 percent of the designs consist of 8-/16-bit MCU-based topology with advanced features, and some even have 32-bit processors to provide enhanced graphic displays and menu-driven user interfaces.

In the context of EMI/EMC, the most preferred approach to circumvent the interference and susceptibility issues is to take a system's view. The routing of the wiring harness, the circuit design, the layout design, operating frequency, power quality, operating environment, and the firmware implementation are some of the important factors that need to be considered.